What are the causes of prominent a waves in JVP?
A prominent a wave in jugular venous pulse indicates a resistance to right ventricular filling, which may be due to RV hypertrophy or RV inflow obstruction.
Those with right ventricular hypertrophy:
Pulmonary stenosis with intact ventricular septum. Right ventricular pressures can go suprasystemic in severe pulmonary stenosis producing severe right ventricular hypertrophy and diastolic dysfunction. This leads right atrial overload and prominent a waves in JVP. If there is a ventricular septal defect as in tetralogy of Fallot, right and left ventricular pressures equalizes and right ventricular pressures cannot become suprasystemic in the presence of a non restrictive ventricular septal defect. Hence the right ventricular hypertrophy is not severe enough to produce right atrial overload and prominent a waves in JVP.
Pulmonary arterial hypertension: In severe pulmonary arterial hypertension (primary pulmonary hypertension or other causes without equalization of ventricular pressures), pulmonary arterial pressures are often suprasystemic and the right ventricular hypertrophy is severe enough to produce right atrial overload and prominent a waves in JVP.
Right ventricular cardiomyopathy
Due to RV inflow obstruction:
Tricuspid atresia: As the right ventricular inflow is not patent, right atrium hypertrophies, causing prominent a waves. This is more likely if the associated atrial septal defect is restrictive.
Tricuspid stenosis: Obstruction of tricuspid valve causes elevation of right atrial pressures and right atrial hypertrophy, causing prominent a waves. Giant a waves often described as "leaping to the eye" are greater in height than usually perceived, as demonstrated by pressure recordings.
Tumors obstructing RV inflow: Depending on severity of obstruction and whether the obstruction is persistent or intermittent, a waves can become prominent in the JVP.
